Expansion pulley



M37 3 1927 F. H. sLEEPER EXPANSION PULLEY Original Filed Jan.14, 1925May 3,1927'. 1,626,701-

F. H. SLEEPER EXPANSION PULLEY' original Filed Jan.14, 1925 zsheets-sheer. 2.

iwi/0f Patented May 3, 1927.

UNITED STATES PATENT -orrisciaJ- ERANK HENRY sLEEPER, or WORCESTER,lvrAssAcnusETTs. AssIGNoaTO SLEEPER e HAETLEY, INC., OE WORCESTER,NAssAcHUsETTs, A CORPORATION or MASSA:

CHUSETTS.' l

EXPANSION .UELE y p Appiicatim;y sied January ,14,- w25/serial No.ziiv.Renewed January 26,1927.

This invention relates to an improvement over a pulley patented' by me'on VJune 3, 1924, No; 1,496,032. This invention has substantiallythesame objects as expressed said patent and inl addition theretoinvolves the simplification of construction and the reduction 1n cost ofmanufacture without reducing the efficiency. l

'By this'inv'ention a pulley for transmit ting powerv is constructed inlsections, each 'section being adapted 'to yield inwardly and`moveoutwa-rdly. Incase of the ,driven pulley the. parts areso arrangedthat when the torque on the shafty increasesthe diameter of the pulleyincreases so that its sp-eedv'will decrease in that case or increase ifthe torqueV decreases. In the case Aof a driving'pulley,

When thepowertransmitted is increased the diameter of the pulley vwillbe'reduced to automatically slowdown the spee'd'of drive. Vhen the loadOn the driving shaft 4decreases the diameter of the pulley willautomatically increase to'fincrease the speed of the driven shafttowhichvthe power is transmitted bythe belt.` Ineither case therelawhich the pulley is loosely mounted will change the size of thepulley. Also yielding istheh'ub 13, withweb 16, This 4hubfis intendedvtio, connect with the y ,p

85 fixed totheV shaft and with its web 16 provided with a series ofpivot studs 1 5. "Pivotally mounted on these studs' 15j are a vseries ofstems' 1 8l Aeach one having apulley rim 'segment 19h11' yIneans'isprovided asin the other case for resisting the motion of the pulleysections in al direction whichfwill decrease'the speed of transmissionof lpower through the pulley.` p More specic'ally stated, this inventioninvolves the mountingl of the pulley segments `to swing on pivotsinstead of sliding, and the location of'thosel pivots far enough awayfrom the, pulley segments, and in suoli a position, that,`with` theslight movement that takes place, no great vdistortion of the circularshapeof the pulley 6will be lapparent in any ordinary use' of thepulley.v This i117 vention also involves the special construction of thepivot arms for supporting thepulley segments so that they will notinterfere with` each other =and sothatthe several parts of, the pulleywill' have linished -be'armg spots ythat will keep them in the properpositions.

f j Otherfobjects and advantagesof thein- "vention will 'appearhereinafter.

l j' Referencefis'to lbe yhadto the'acconipanyf ies drawings in which# yFig. 1 is a sideview of a driven pulley in contracted condition.constructed' l inl accordance' invention lwith' parts-ebrplr'en as"illustrated tive rotation of 'theY pulley and sha-fton "the disc 11 asindicated and 'at ai distan@ t away andin section to show'interior conestruction;r v` 'l F ig. Q is a'sectional view on the broken Figj isayrear'vew of the pulley'with partsbrOken away and showing it in a moreexpanded condition than'in Fig." 1'; 4 is an edge view/of 'Oneof thepulley segments `with all the'parts at the'lreto that really constitutea lpart anc f 'Fig 5 is atransverse sectional 'view on'the line'f ofFigjl. y I'ha've illustrated ley but the driving the same principlemerely the driven pulpa'tentffThe driven it 'the/hub of a flat diScwl'l.Thisdisc is provi-ded with a series Ofcam slots 12 located inenlargements 9 extending inwardly pulley is constructed on with' theparts changed in'my above mentioned` shaft 10 has keyed upon from thecircumference and tangentially.

They are all tangent to a circle'drawn from the center through theircorners which are nearest the shaft, located vat equal definite anglestop "radial lines at! these points.H l

Looselymounted on the c lriven-shaftfhl() v shaftv through the disci`11.1 "Itr is shown Las bearing up against'a collar 14 of thepulley. v

itsjout'er end, preferably integral therewith. y f

These segments v19 taken 'together lconstitute the entire rimofthe/pulley and extendo'ver in Fig. 2. It'will be noted that'th'e"studs 15' are arranged suchposition that the pulley rim segments swingfout and inVOn an arc having as long aradius as can be; convenientlyprovided and in such a `directionV thatv when they 'swing vout theydo'notseriously-modify the circular shape of* the rim.Vv As shown inFig. 3, 'wheniexe panded considerably it would' never i be oticed thatthe pulley is, not perfectly oircular.l 1 this purpose, each Studisplaced olit- Ward' s :far 'Wy AffQm. th Shaft-SPOSSM rom [the pulley runsegioo #with wm ,CAMA-@ee Laet Fori this purposethey are bent-at 17 soas i tion or stud 20 on which is rotatably mount.

segments is equal to I astud 22 ,to which 4o i .1 .oftheCorrespondingrimA segment 19.

to avoid engagement of any stem with thev next two; Each stem projectsunderl the next one on one side of its pivot end and over the pivotedend of the one on the other side.

Each stem 18 is provided with a projeced a cam roll 21,v engaging in oneofsaid cam slots Vv12.v Of course it will be understood that thev.number ofthe'se stems and pulley the number of camslots 121andeach ofthese rolls 21 is located in one of the cam slots. On both sides of eachi stein vis-located a `plane finish spot 25those on one side lengagingthe plane surface of theprojections 9 onthedisc 11 and those on ltheother side engaging the inturned edge ofthe disc 16, so that the twodiscs rest against plane surfaces opposite each other. On the rear ofYeach rim segment there is ,Y one end of ay tension spring 23is secured.The other end of the spring is secured to a projection 24 on a ring ywhich is fixed 'on the hub 13.. v.These springs are arranged vtangent tothis ring and inlsuch position as'shownin Fig.l 3 as to tend thegreatest advanare transverse lto ai line drawn from each pivot totheopposite end l- 'This construction lis employed ltoholdfthe Y rim'segments in towardtheceiiter and in that way they tend to resistincrease inthe size of th'edriven-pulley and consequent re.- duction ofspeed ratio. In the Ycase ofthe driven pulley they also .resist the`action of centrifugal force, if the, pulleyl is driven fast yenough tobring thatinto action-suliiciently to move these segments-*In place ofthe ing changes in` diameter of the pulley stated.

In' the Vcase i ofboth drivingy and driven pulley thesey springsresist achange `that would cause a decrease in the speed of transmission. Thepulley 4isjrotated in the direction indicated by the` arrows,namely,fanti- Vclockwise as'fviewed inrFig. ,1j-and, clockwise y asvewedin Fig. 3. y It will be seen that as power is transmitted torque willexpandthe pulley. Therefore,

fshaft.- Y

to swing the rimsegmentsinwardly about their pivots 15 at tage, thatyis, they 1planed out and fittedv `that there are no guiding surfaces andcarrying` 18 `to the-rolls21`v ,s the slots 12 to the disc -11y ffforrotating the shaft the pulley will transmit its power to the shaft 10 ata slower speed if it is a driven pulley. This change in speed isgoverned automatically by the resistance on the ldriven Furthermorewhenever less resistance is placed on the shaft the cam" action on therolls will tend to move the rim sections inwardly. That can be vdoneonly by relative motion of the rolls in the slots toward the inner endsthereof. This reduces the'diameter of `the pulley .andl will increasethe speed ratio and .drive the shaft faster. .If

centrifugal force bel disregarded the only thing causing a ychange inthe diameter of the pulley is a change in the torque.

When the invention is applied to -a driving pulley, all the elementsVVare made inthe same way exceptthat compression springs ,are`substituted for the springs 23 the direc- -tion ofl rotation being thesame. Now if this shaft be consideredv as the driver, the rim is drivenfrom y power required will'tendto pull the segments of the pulley in toreduce its size thus slowing downr automatically. It ywill be understoodthat leys, one. as a4 driver and the other as ,a .driven pulleyconstructed as described.v

In a construction of this kind, there is a minimum of friction tendingto 'resist the Vso it and an increase in the speed of `the ybelt l .itis my intention topemploy a pair of pulmovement of the pulley segmentsout 'l and in and no chance of their or. bound in position. Furthermorethere are no guiding surfaces that will have to be true on account of4wear." VBy that I mean at the forward. and rear'sides of the arms 18asin my `prior patent. Itj is asimple construcand may get vout ofrgetting cramped viet tionk to manufacture and av comparatively the partsare assembled inexpensive one,

it will work vconveniently very easily, and f after a comparativelyAlarge amount of. wear.

Although I have illustrated and described only a single form oftheinvention I am aware of the fact that modifications can be made thereinby anyioerson skilled yin the art without departing from thescope of theinvention as expressed in the claims. Therefore` I do not wish to belimited to all the details of construction herein shown:- and.

.described but what I do claim is v 1. An automatically expansible andcontractible pulley, comprising a plurality =of iisl rim segments, eachhaving a stemprojecting l inwardly at an Vangle to a 'radialv line, aweb member loose ony the shaftof the pulley studs yon which said stemsare .pivoted, a disc resist movement of said segments'.

fast on the shaftl and having 1 cam slots-equal innumber to saidsegments,

, 2. An expansible pulley, comprising a dise i fast on the pulleyshaftvand hav-ing a plurality of angular slots tangential to a commoncircle, a hulo and Web member loose on the shaft and provided With aplurality of .pivot studs, a plurality of rim segments each havingv astem projecting inwardly at an angle to a radial line and pivotallyconnected to said studs, a. roller carried by each of said stemsintermediate its ends and engaging in one of said slots, and springmeans vto resist radial movement of said segments.

3. An automatically expansihle and Con-y y traetible pulley, comprisinga dise 4fast on the shaft 1 and provided With cam slots, a

second dise loose on the shaft, a plurality of rim segments,` eachhaving a' stem pivoted to Said loose dise, a roller on each of saidstems engaging one of said slots, and resil-v 4 ient means to resistradial movement of said segments.

In testimony whereof affixed my signature. 1

FRANK HENRY sLi'iEPER.`

I have hereunto

